Surface Unsaturated Sulfur Modulates Pt Sub-Nanoparticles on Tandem Homojunction CdS for Efficient Electron Extraction

摘要

The metal-semiconductor interfacial photocarrier extraction and utilizationare crucial for boosting photocatalytic activity, and the construction ofinterfacial chemical bonds to anchor the metal active sites is an emergingdirection to facilitate interfacial photocarrier extraction. Herein, interfacialPt-S bonds are designed via an in situ photoreduction to precisely anchor Ptsub-nanoclusters (SNCs) on the tandem homojunction CdS (Pt-CdS_x-T). Theoptimized Pt_(0.02)-CdS_x-T photocatalyst exhibits an impressive hydrogen evolutionrate of 854.2 μmol h~(?1) with an apparent quantum yield of 43.55% at 470 nm,which is nearly 13 times that of pristine CdS. Systematic investigations revealthat the abundant coordination-unsaturated S atoms on CdS_x-T act as sites toanchor Pt SNCs and the thus formed interfacial Pt-S bonds accelerate the metalsemiconductorinterface directional photocarriers transfer. The homojunctionCdS_x-T with its tandem potential barrier promotes the separation ofphotocarriersvia an internal electrostatic field, and the metal-semiconductorinterface electron transfer kinetics and H* adsorption capacity depend onthe Pt SNCs size as confirmed by the surface photovoltage spectroscopy anddensity functional theory calculations. This work affords a new perspective forthe exploitation of precisely dispersed cocatalysts on homojunction catalyststo achieve high-efficiency photocatalytic hydrogen evolution.